426,000 kilometers on the odometer and a battery that’s still showing impressive health, the scene feels almost unreal. Yet this is the story of an electric SUV used as a taxi in the United Kingdom, bought at a bargain by a YouTuber. The big question: could the high‑voltage battery still cover real-world distances, or would the venture spiral into a nightmare? And in this case, the numbers tell a story that’s rather unique.
At the heart of the tale is a Kia Niro EV from 2021, a former British taxi. It’s sitting on roughly 426,000 km, tallying up in just five years of heavy service. Efficient Alex tracked it down at auction for £4,100, about €4,800. After months of restoration, one question remained: was the battery really worth the gamble? The answer didn’t follow the script many would have expected.
A 426,000-km Kia Niro EV Put Through Its Battery Health Test in the UK
This Kia Niro EV led a busy life as a taxi, racking up an average of about 88,000 miles per year over five years. “Because this car with 426,000 km logged roughly 88,000 miles per year for the last five years,” Efficient Alex explained in his video, cited by Supercar Blondie. The relentless use left mechanical signs—like worn bearings in the motor and the transmission. But the big unknown remained the high‑voltage battery. Replacing it can cost thousands of dollars, i.e., thousands of euros.
Under the floor, this Niro houses a 64 kWh usable battery, about 67.5 kWh gross, with NMC chemistry. It benefits from an active thermal management system designed to keep the cells within a controlled temperature range. The data reported by the on-board computer tell the tale of a grind‑through life. The Niro logged 22,757 hours of operation, 1,955 charging sessions, and roughly 57,900 kWh of energy charged. A reminder that the challenge of buying a used electric isn’t just the total miles on the clock. Efficient Alex looked at a Geotab study that cited an average battery degradation of around 2.3% per year for electric cars. Applying that figure, he estimated the Niro should still show about 88.5% capacity after five years.
85.3% Battery Health for the 426,000-km Kia Niro
To verify the battery’s condition, Efficient Alex first plugged in an OBD adapter and used the Car Scanner app. The tool pulled the data from the battery management system, the BMS. Result: a State of Health (SoH) reported at 100%, as if the pack were fresh from the factory. A second test performed by Vault Test confirmed the 100% figure. Again, this reading relied on the manufacturer’s internal BMS data. Specialists noted that Kia computes SoH relative to the usable capacity of 64 kWh. As long as that value remains the reference, the BMS can continue to show 100%. A piece of reserve capacity may, however, already have faded behind the scenes. For an independent measurement, Efficient Alex turned to AVILOO for a Flash Test, marketed as Battery Health Check. This time, the result was notably different. SoH registered at 85.3%, with the cells described as well balanced.
Even with this figure below the BMS’s 100%, the overall picture is still favorable for a 426,000-km Niro. Efficient Alex notes that the car charges normally and, depending on the routes driven, can still deliver nearly 480 km on a real-world full charge. “You can own a high-mileage electric vehicle, and if it’s well maintained, it can really hold onto battery health,” one of the specialists commented during the evaluation. For Efficient Alex, the takeaway for buyers of ultra‑high-mileage EVs is clear: don’t be instantly scared off by a big odometer, but do insist on an independent battery check before shelling out thousands on a used model. This advice lands particularly hard given that Kia’s battery warranty covers eight years or 160,000 km (roughly 100,000 miles). It sets a 70% capacity threshold, well below the 85.3% measured on this Niro at 426,000 km. For French readers eyeing the American used-EV market, this kind of real‑world mileage matters more than ever.
